DESCRIPTION (Adapted from applicant's description): The purpose of this study is to delineate the epidemiology of infant admissions to an academic tertiary care medical center following an apparent life-threatening event (ALTE), with particular emphasis on the incidence of shaken baby syndrome; and to assess the utility and cost of including, in the evaluation of an ALTE, specific tests that can detect shaken baby syndrome. All infants under one year of age who are admitted to Westchester County Medical Center for evaluation of ALTE during a 21-month period will be enrolled in the study. Hospital and follow-up data will be prospectively gathered to determine the epidemiology (etiology and outcomes) of ALTEs. Based on results of a standardized diagnostic evaluation protocol, subjects will be classified into one of four etiologic categories: shaken baby syndrome, other etiology involving brain, etiology not involving brain, or etiology unknown. In addition, the study will determine the marginal improvement in the detection of shaken baby syndrome resulting from the inclusion of specific diagnostic tests (fundoscopic retinal examination and head CT scan) in the evaluation of ALTE, as well as the marginal cost of those tests.